Vehicles such as automobiles are normally mounted with a bumper designed to attenuate the shock of collision, but most of the conventional bumpers are made of a metal material with metallic plating.
Such metal-made bumpers have indeed an aesthetic merit but are limited in elasticity and hence poor in shock absorptivity. Efforts for overcoming such problems while satisfying the intensified safety regulations have led to the development of a shock absorbing bumper composed of an elastic external member made of an elastic material such as an urethane elastomer and a flexible core member made of urethane foam or such.
Such an elastic bumper, although excellent in shock absorptivity, still has the problem of poor outward appearance. An answer to this question is the integral provision of a decorative facing on the surface portion of the external member.
The decorative face used for this purpose is of high rigidity as it is usually formed from metal or aluminized resin strips, so that in the event of collision, although the striking energy itself may be absorbed, the decorative facing would suffer plastic deformation and become unable to restore to its original shape because such a decorative facing is less elastic than the external and core members. Thus, the original facing design would be impaired even by a slight degree of collision, for example by initial collision in low-speed running at, say, 8 kg/hr, and even though the shock sbsorbing performance of the bumper per se is undamaged, its replacement would be necessitated. Such a shock absorbing bumper with a facing, therefore, had the disadvantage in high maintenance cost in addition to the trouble involved in incorporating such a facing.